Since the iOS 18 and Xcode 16, I've been getting some really strange SwiftData errors when passing @Model classes around. The error I'm seeing is the following: SwiftData/BackingData.swift:409: Fatal error: This model instance was destroyed by calling ModelContext.reset and is no longer usable. PersistentIdentifier(id: SwiftData.PersistentIdentifier.ID(url: x-coredata://34EE9059-A7B5-4484-96A0-D10786AC9FB0/TestApp/p2), implementation: SwiftData.PersistentIdentifierImplementation) The same issue also happens when I try to retrieve a model from the ModelContext using its PersistentIdentifier and try to do anything with it. I have no idea what could be causing this. I'm guessing this is just a bug in the iOS 18 Beta, since I couldn't find a single discussion about this on Google, I figured I'd mention it. if someone has a workaround or something, that would be much appreciated.

The 'unique' attribute is a really nice feature, BUT. In some of my apps, the unique identifier for an object is a combination of multiple attributes. (Example: a book title is not unique, but a combination of book title and author list is.) How do I model this with SwiftData? I cannot use @Attribute(.unique) on either the title OR the author list, but I want SwiftData to provide the same "insert or update" logic. Is this possible?

Hi everyone, Have anybody faced with Core Data issues, trying to migrate the project to Xcode16 beta 4? We are using transformableAttributeType in some entities, with attributeValueClassName = "[String]" and valueTransformerName = "NSSecureUnarchiveFromData". It is working just fine for years, but now I am trying to run the project from Xcode16 and have 2 issues: in Xcode logs I see warning and error: CoreData: fault: Declared Objective-C type "[String]" for attribute named alertBarChannels is not valid CoreData: Declared Objective-C type "[String]" for attribute named alertBarChannels is not valid periodically the app crashes when we are assigning value to this attribute, with error: Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFConstantString characterAtIndex:]: Range or index out of bounds' Once again, in Xcode 15 it works fine, and it was working for years. Cannot find any information about what was changed in the framework... Thank you in advance for any information, which could clarify what is going on.

I have an app with fairly typical requirements - I need to insert some data (in my case from the network but could be anything) and I want to do it in the background to keep the UI responsive. I'm using SwiftData. I've created a ModelActor that does the importing and using the debugger I can confirm that the data is indeed being inserted. On the UI side, I'm using @Query and a SwiftUI List to display the data but what I am seeing is that @Query is not updating as the data is being inserted. I have to quit and re-launch the app in order for the data to appear, almost like the context running the UI isn't communicating with the context in the ModelActor. I've included a barebones sample project. To reproduce the issue, tap the 'Background Insert' button. You'll see logs that show items being inserted but the UI is not showing any data. I've tested on the just released iOS 18b3 seed (22A5307f). The sample project is here: https://hanchor.s3.amazonaws.com/misc/SwiftDataBackgroundV2.zip

I'm using SwiftData with an @Model and am also using an @ModelActor. I've fixed all concurrency issues and have migrated to Swift 6. I am getting a console error that I do not understand how to clear. I get this error in Swift 6 and Swift 5. I do not experience any issue with the app. It seems to be working well. But I want to try to get all issues taken care of. I am using the latest Xcode beta. error: the replacement path doesn't exist: "/var/folders/1q/6jw9d6mn0gx1znh1n19z2v9r0000gp/T/swift-generated-sources/@_swiftmacro_17MyAppName14MyModelC4type18_PersistedPr> opertyfMa.swift"

Posting here to see if folks have workarounds or if I have a misunderstanding of SwiftData supported types. In adopting SwiftData, I have swiftData properties of collection type (Array or Set - both have this issue). E.g: @Model final class Item { var timestamp: Date var strings = ["aa", "bb"] var display: String { strings.joined(separator: " ") } init(timestamp: Date) { self.timestamp = timestamp } } So far in development I haven't had issues on iOS 17, but on the iOS 18 betas 4-5 the app logs show the following error: "fault: Could not materialize Objective-C class named "Array" from declared attribute value type "Array<String>" of attribute named strings" It happens immediately in my app when creating an object with a collection attribute. In a minimal test example, the error log appears only after a few minutes and doesn't seem to affect the template app's basic functionality. Anyone else running into this? Was filed as FB14397250

I am using SwiftData for storage and have a view that uses the @Query property wrapper with a sort descriptor that points to a relationship on a model. In a release build on device running iOS 18.3, the app crashes. This is the line that crashes: @Query(sort: \Item.info.endDate, order: .reverse) private var items: [Item] Item has a relationship to ItemInfo, which is where the endDate property is defined. This code works in debug and on a simulator. In the project referenced here: https://github.com/lepolt/swiftdata-crash, change the scheme build configuration to “Release” and run on device. The app will crash. Using Xcode Version 16.2 (16C5032a) iPhone 12, iOS 18.3 (22D60)

One question I often see on DevForums and in my day DTS job is if a Core Data object managed by NSPersistentCloudKitContainer can be shared with other iCloud users. The answer is yes but you need to do it using CloudKit API directly because NSPersistentCloudKitContainer doesn’t support CloudKit shared database (CKContainer.sharedCloudDatabase) today. Assuming you have a Core Data object, let’s say a document, that you’d like to collaborate with your colleagues: You are the document owner and can use NSPersistentCloudKitContainer to fully manages the document and synchronize it across your devices. You can grab a CloudKit record associated with your document from NSPersistentCloudKitContainer using record(for:) or recordID(for:), and share it to your colleagues using UICloudSharingController. See our Sharing CloudKit Data with Other iCloud Users - https://developer.apple.com/documentation/cloudkit/sharing_cloudkit_data_with_other_icloud_users sample for how to share a CloudKit record. After accepting the sharing, your colleague, as a participant, can view or edit the shared document. The document resides in the participant’s CloudKit shared database and you have to manage it with your own code. When your colleague edits and saves the shared document, the changes go to the owner’s private database, and eventually synchronize to NSPersistentCloudKitContainer on the owner side.  As you can see, you need to implement #2 and #3 with your own code because NSPersistentCloudKitContainer can’t manage the data in the participant's shared database. If you have any difficulty after going through the above sample code, you can contact Apple’s DTS for help.

I'm trying to handle the serverRecordChanged return code you get in CKError when you have a conflict and your using the savePolicy of ifServerRecordUnchanged. According to the CKError.Code.serverRecordChanged documentation, I should be receiving all three records that I need to do a 3-way merge. The problem is that the ancestorRecord (CKRecordChangedErrorAncestorRecordKey can also be used to look it up in the userInfo) doesn't actually contain a record. It only contains the record metadata. Is there something I need to be doing to get the full ancestorRecord in the CKError? If not is it possible to query iCloud for the ancestorRecord? Given that iCloud has the change history (as I understand it), then it is theoretically possible. I just don't know how to do it if it is possible. Are 3-way merges even possible? The design of the serverRecordChanged looks like that is the intent, but I can't see how to do it with the data that CloudKit is providing.

When trying to run my document-based iPad app using iPadOS 18 beta and Xcode 16 beta, I get an error like the following after opening a document: Thread 1: Fatal error: Failed to identify a store that can hold instances of SwiftData._KKMDBackingData<MyProject.MyModel> from [:] In order to help track down what is going wrong, I downloaded the sample app from WWDC23 session "Build an app with SwiftData" found here: https://developer.apple.com/documentation/swiftui/building-a-document-based-app-using-swiftdata When I try to run the end-state of that sample code, I get a similar error when running the app on my iPad and creating a new deck: Thread 1: Fatal error: Failed to identify a store that can hold instances of SwiftData._KKMDBackingData<SwiftDataFlashCardSample.Card> from [:] Given that the sample project is generating the same error as my own project, is this a problem with SwiftData and document-based apps in general? Or is there a change of approach that I should try?

The NSPersistentCloudKitContainer synchronization between core data and iCloud was working fine with phone 15.1. Connected a new iPhone iOS 15.5, it gives error: CoreData: debug: CoreData+CloudKit: -[NSCloudKitMirroringDelegate managedObjectContextSaved:](2504): <NSCloudKitMirroringDelegate: 0x28198c000>: Observed context save: <NSPersistentStoreCoordinator: 0x2809c9420> - <NSManagedObjectContext: 0x2819ad520> 2022-12-05 13:32:28.377000-0600 r2nr[340:6373] [error] error: CoreData+CloudKit: -[NSCloudKitMirroringDelegate _importFinishedWithResult:importer:](1245): <PFCloudKitImporter: 0x2837dd740>: Import failed with error: Error Domain=NSCocoaErrorDomain Code=4864 "*** -[NSKeyedUnarchiver _initForReadingFromData:error:throwLegacyExceptions:]: incomprehensible archive (0x53, 0x6f, 0x6d, 0x65, 0x20, 0x65, 0x78, 0x61)" UserInfo={NSDebugDescription=*** -[NSKeyedUnarchiver _initForReadingFromData:error:throwLegacyExceptions:]: incomprehensible archive (0x53, 0x6f, 0x6d, 0x65, 0x20, 0x65, 0x78, 0x61)} CoreData: error: CoreData+CloudKit: -[NSCloudKitMirroringDelegate _importFinishedWithResult:importer:](1245): <PFCloudKitImporter: 0x2837dd740>: Import failed with error: Error Domain=NSCocoaErrorDomain Code=4864 "*** -[NSKeyedUnarchiver _initForReadingFromData:error:throwLegacyExceptions:]: incomprehensible archive (0x53, 0x6f, 0x6d, 0x65, 0x20, 0x65, 0x78, 0x61)" UserInfo={NSDebugDescription=*** -[NSKeyedUnarchiver _initForReadingFromData:error:throwLegacyExceptions:]: incomprehensible archive (0x53, 0x6f, 0x6d, 0x65, 0x20, 0x65, 0x78, 0x61)} I go back and try with my old iPhone iOS 15.1, gives same error.

How does SwiftData work with background operations? CoreData had background context that could be used to avoid UI hang for heavy operations. Is there an equivalent in SwiftData, and if so, do I have to merge changes or does it save directly to persistent store?

Hello everyone, I used SwiftData for v1 of an app and am now trying to make changes to the schema for v2. I created the v2 schema that adds a property to one of the models. I need to populate the new property so I made a custom migration using didMigrate. However that doesn't seem to matter what I do in the migration because creating the ModelContainer throws an error before didMigrate ever gets called. The error is: Unresolved error loading container Error Domain=NSCocoaErrorDomain Code=134060 "A Core Data error occurred." UserInfo={NSLocalizedFailureReason=Instances of NSCloudKitMirroringDelegate are not reusable and should have a lifecycle tied to a given instance of NSPersistentStore.} Higher up in the Xcode output I see things like this (in order): Request 'D25A8CB8-7341-4FA8-B2F8-3DE2D35B5273' was cancelled because the store was removed from the coordinator. BUG IN CLIENT OF CLOUDKIT: Registering a handler for a CKScheduler activity identifier that has already been registered CloudKit setup failed because it couldn't register a handler for the export activity. There is another instance of this persistent store actively syncing with CloudKit in this process. How can I know from this output what I am doing incorrectly? Any idea what I should take a look at or try to do differently? This is a simple app with three models and nothing fancy. The only change in the schema is to add a property. The new property is declared as optional and has an inverse that is also declared as optional. Thanks for any insight!

I have an Apple app that uses SwiftData and icloud to sync the App's data across users' devices. Everything is working well. However, I am facing the following issue: SwiftData does not support public sharing of the object graph with other users via iCloud. How can I overcome this limitation without stopping using SwiftData? Thanks in advance!

When I logged into my cloudkit console to inspect the database for some debugging work I couldn't access the private database. It keeps saying "failed to access iCloud data, please signi n again". No matter how many times I sign in again, whether with password or passwordless key it keeps saying the same thing. It says that message when I click on Public database, and private and shared databases are below it. I only noticed this a couple of days ago. It's done this in the past, but I eventually got back into the database but I don't know what changed to make it work.

My use case is the following: Every user of my app can create as an owner a set of items.  These items are private until the owner invites other users to share all of them as participant. The participants can modify the shared items and/or add other items. So, sharing is not done related to individual items, but to all items of an owner. I want to use CoreData & CloudKit to have local copies of private and shared items. To my understanding, CoreData & CloudKit puts all mirrored items in a special zone „com.apple.coredata.cloudkit.zone“. So, this zone should be shared, i.e. all items in it. In the video it is said that NSPersistentCloudKitContainer uses Record Zone Sharing optionally in contrast to hierarchically record sharing using a root record. But how is this done? Maybe I can declare zone „com.apple.coredata.cloudkit.zone“ as a shared zone?

Recently I've been working on a demo project called iLibrary. The main goal was to learn more about CloudKit and SwiftData. After a while I noticed that there were some hangs/freezes when running the app in debug mode. I first tried this with Xcode 15.4 and iOS 17.5. Here the hang only appears at the beginning, but only for a few seconds. But when I exit debug mode, there are no more hangs. With Xcode 16 beta 4 and iOS 18 it looks completely different. In this case, the hangs and freezes are always present, whether in debug mode or not. And it's not just at the beginning, it's throughout the app. I'm aware that this is still a beta, but I still find this weird. And when I profile this I see that the main thread gets quite overloaded. Interestingly, my app doesn't have that many operations going on. So I guess something with the sync of SwiftData or my CloudKitManger where I fetch some records from the public database is not running fine. Lastly, I wanted to delete the iCloud app data. So I went to Settings and tried to delete it, but it didn't work. Is this normal? Does anyone have any idea what this could be? Or has anyone encountered this problem as well? I'd appreciate any support. My project: https://github.com/romanindermuehle/iLibrary

I'm using NSPersistentCloudKitContainer with Core Data and I receive errors because my iCloud space is full. The errors printed are the following: <CKError 0x280df8e40: "Quota Exceeded" (25/2035); server message = "Quota exceeded"; op = 61846C533467A5DF; uuid = 6A144513-033F-42C2-9E27-693548EF2150; Retry after 342.0 seconds>. I want to inform the user about this issue, but I can't find a way to access the details of the error. I'm listening to NSPersistentCloudKitContainer.eventChangedNotification, I receive a error of type .partialFailure. But when I want to access the underlying errors, the partialErrorsByItemID property on the error is nil. How can I access this Quota Exceeded error? import Foundation import CloudKit import Combine import CoreData class SyncMonitor { fileprivate var subscriptions = Set<AnyCancellable>() init() { NotificationCenter.default.publisher(for: NSPersistentCloudKitContainer.eventChangedNotification) .sink { notification in if let cloudEvent = notification.userInfo?[NSPersistentCloudKitContainer.eventNotificationUserInfoKey] as? NSPersistentCloudKitContainer.Event { guard let ckerror = cloudEvent.error as? CKError else { return } print("Error: \(ckerror.localizedDescription)") if ckerror.code == .partialFailure { guard let errors = ckerror.partialErrorsByItemID else { return } for (_, error) in errors { if let currentError = error as? CKError { print(currentError.localizedDescription) } } } } } // end of sink .store(in: &subscriptions) } }

I have a simple app that uses SwiftUI and SwiftData to maintain a database. The app runs on multiple iPhones and iPads and correctly synchronises across those platforms. So I am correct setting Background Modes and Remote Notifications. I have also correctly setup my Model Configuration and ModelContainer (Otherwise I would expect syncing to fail completely). The problem arises when I run on a Mac (M1 or M3) either using Mac Designed for iPad or Mac Catalyst. This can be debugging in Xcode or running the built app. Then the app does not reflect changes made in the iPhone or iPad apps unless I follow a specific sequence. Leave the app, (e.g click on a Finder window), then come back to the app (i.e click on the app again). Now the app will show the changes made on the iPhone/iPad. It looks like the app on the Mac is not processing remote notifications when in the background - it only performs them when the app has just become active. It also looks like the Mac is not performing these sync operations when the app is active. I have tried waiting 30 minutes and still the sync doesn't happen unless I leave the app and come back to it. I am using the same development CloudKit container in all cases

My app has been in the App Store a few months. In that time I've added a few updates to my SwiftData schema using a MigrationPlan, and things were seemingly going ok. But then I decided to add CloudKit syncing. I needed to modify my models to be compatible. So, I added another migration stage for it, changed the properties as needed (making things optional or adding default values, etc.). In my tests, everything seemed to work smoothly updating from the previous version to the new version with CloudKit. So I released it to my users. But, that's when I started to see the crashes and error reports come in. I think I've narrowed it down to when users update from older versions of the app. I was finally able to reproduce this on my end, and Core Data is throwing an error when loading the ModelContainer saying "CloudKit integration requires that all attributes be optional, or have a default value set." Even though I did this in the latest schema. It’s like it’s trying to load CloudKit before performing the schema migration, and since it can’t, it just fails and won’t load anything. I’m kinda at a loss how to recover from this for these users other than tell them to delete their app and restart, but obviously they’ll lose their data that way. The only other idea I have is to setup some older builds on TestFlight and direct them to update to those first, then update to the newest production version and hope that solves it. Any other ideas? And what can I do to prevent this for future users who maybe reinstall the app from an older version too? There's nothing special about my code for loading the ModelContainer. Just a basic: let container = try ModelContainer( for: Foo.self, Bar.self, migrationPlan: SchemaMigration.self, configurations: ModelConfiguration(cloudKitDatabase: .automatic) )